1. Field of the Invention
The present invention relates to apparatus for removing heat from electronic devices. In particular, the present invention relates to a heat sink having a load centering mechanism.
2. State of the Art
Higher performance, lower cost, increased miniaturization of integrated circuit components, and greater packaging density of integrated circuits are ongoing goals of the microelectronic and computer industry. As these goals are achieved, microelectronic dice become smaller. Accordingly, the density of power consumption of the integrated circuit components in the microelectronic die has increased, which, in turn, increases the average junction temperature of the microelectronic die. If the temperature of the microelectronic die becomes too high, the integrated circuits of the microelectronic die may be damaged or destroyed.
Various apparatus and techniques have been used and are presently being used for removing heat from microelectronic dice. One such heat dissipation technique involves the attachment of a heat dissipation device to a microelectronic die. One known embodiment, as shown in FIG. 3a, comprises a pin grid array-type (xe2x80x9cPGAxe2x80x9d) microelectronic die 202 placed in a socket 204 mounted on a carrier substrate 206, wherein pins 208 extending from the microelectronic die 202 make electrical contact with conductive vias 212 in the socket 204. The socket 204 is, in turn, in electrical contact (not shown) with the carrier substrate 206. The heat dissipation device 220 (shown as a finned heat sink having a plurality of fins 222) is kept in contact with the microelectronic die 202 with a spring clip 224 (see also FIG. 3b), which spans the heat dissipation device 220 and connects to the socket 204. Conductive grease or other such thermal interface 226 is placed between the microelectronic die 202 and the heat dissipation device 220. The disadvantage of this assembly is that the spring clip 224 distributes a disproportionate, lateral force or loading across the microelectronic die 202, which may cause cracking of the microelectronic die 202.
In order to prevent disproportionate loading, two load centering techniques have been developed. FIGS. 4a and 4b illustrate one technique for load centering comprising a secondary clip 240 attached to or snapped on a spring clip 234. The force imposed on the heat dissipation device 208 by the spring wire 234 is directed through the secondary clip 240. Thus, the secondary clip 240 can be positioned at any desired location on the spring clip 234 to provide loading in that position. The disadvantage with using a secondary clip 240 for load centering is that it requires additional processing steps to correctly place the secondary clip 240.
FIG. 5 illustrates a second technique for load centering comprising a spring clip 242 having an altered portion 244. The altered portion 244 may comprise a bend or a series of bends in the spring clip 242. Thus, when the spring clip 242 is attached, the force imposed on the heat dissipation device 208 by the spring clip 242 is directed through the altered portion 244. Thus, the altered portion 244 may be positioned at any desired location on the spring clip 242 to provide loading in that position. The disadvantage with using the spring clip 242 is that forming the altered portion 244 tends to reduce the retention force of the spring chip 242.
Therefore, it would be advantageous to develop a heat dissipation device having a load centering mechanism, which overcomes the disadvantages of known load centering mechanisms.